Dmitry

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12 years, 3 days

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These are questions asked by Dmitry

Hello all,

I have the following equation:

N*exp(-(1/2)*eta*epsilon*(N*alpha*epsilon*w+2*N*w*C[max]-alpha*epsilon*z-2*Q1*alpha)/(w*N))*S1*upsilon*w-N*S1*upsilon*w+K1^2*alpha*eta*z*epsilon+K1*alpha*eta*z*epsilon*S1 = 0

in which I need to find solution for epsilon (analytical solution) when epsilon>0.  

Thanks,

Dmitry

 

Hello,

 

I have the following condition with two unknowns: t1 and t3:

-N*exp(Q1*alpha*eta*t1/(N*w))*exp(-(((N*w-z)*t1^2+((-N*w+z)*t3+2*Q1)*t1+(1/2)*t3*(t3*(N*w-z)-2*Q1))*alpha-2*N*w*C[max]*(t1-(1/2)*t3))*eta/(N*w))*S1*upsilon*w+N*exp(Q1*alpha*eta*t1/(N*w))*exp(-(((N*w-z)*t1^2+((-N*w+z)*t1+2*Q1)*t1+(1/2)*t1*((N*w-z)*t1-2*Q1))*alpha-2*N*w*C[max]*(t1-(1/2)*t1))*eta/(w*N))*S1*upsilon*w+K1^2*exp((1/2)*t1^2*alpha*eta*z/(N*w))*exp(-(1/2)*t1^2*alpha*eta)*exp(t1*eta*C[max])*alpha*eta*t1*z-K1^2*exp((1/2)*t1^2*alpha*eta*z/(N*w))*exp(-(1/2)*t1^2*alpha*eta)*exp(t1*eta*C[max])*alpha*eta*t3*z+K1*exp((1/2)*t1^2*alpha*eta*z/(N*w))*exp(-(1/2)*t1^2*alpha*eta)*exp(t1*eta*C[max])*S1*alpha*eta*t1*z-K1*exp((1/2)*t1^2*alpha*eta*z/(N*w))*exp(-(1/2)*t1^2*alpha*eta)*exp(t1*eta*C[max])*S1*alpha*eta*t3*z = 0

I know that this condition holds when t1=t3. Does there exist an additional solution for t1 and t3 which satisfies this condition?

Thanks,

Dmitry

Hi,

I have a system of diff equations (see below). I am trying to obtain analytical solution. when I assume that z=wN, I receive such solution. Do anybody have idea if I know that z>wN, does this system has an analytical solution?

diff(K(t), t) = -(1/2)*(Q(t)^2*alpha^2*eta*upsilon-2*eta*alpha*(N*upsilon*w*C[max]-z*alpha*K(t))*Q(t)+N*w*(-2*C[max]*z*eta*alpha*K(t)+upsilon*((-N*w+z)*alpha+N*C[max]^2*w*eta)))*K(t)/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

diff(Q(t), t) = (1/2)*(-z*(Q(t)^2*alpha^2*eta-2*N*Q(t)*alpha*eta*w*C[max]+w*(w*(eta*C[max]^2-alpha)*N+z*alpha)*N)*K(t)-2*N*upsilon*w*(N*w-z)*(C[max]*w*N-alpha*Q(t)))/((C[max]*w*N-alpha*Q(t))*upsilon*N*w)

K(0) = K0, Q(0) = Q0

Thanks,

Dmitry

Hello,
I have a system of first order diff. equations which I would like to solve symbolically. Unfortunately, Maple does not solve the system. Do anybody have suggestions how can I solve this system (please see below):

diff(S(t), t) = -eta*(C[max]*w*N-alpha*Q(t))*K(t)*S(t)/(w*N*(S(t)+K(t))),

diff(K(t), t) = S(t)*((z*eta*alpha*(C[max]*w*N-alpha*Q(t))*S(t)-upsilon*(eta*alpha^2*Q(t)^2-2*C[max]*w*N*eta*alpha*Q(t)+((-N*w+z)*alpha+N*C[max]^2*w*eta)*N*w))*K(t)^2+(2*((1/2)*z*eta*(C[max]*w*N-alpha*Q(t))*S(t)+N*w*upsilon*(N*w-z)))*S(t)*alpha*K(t)+N*S(t)^2*w*alpha*upsilon*(N*w-z))/((K(t)^2*alpha*z+3*S(t)*K(t)*alpha*z+S(t)*(2*S(t)*z*alpha+upsilon*(C[max]*w*N-alpha*Q(t))))*(S(t)+K(t))*N*w),

diff(Q(t), t) = (-alpha*z*(z*eta*(C[max]*w*N-alpha*Q(t))*K(t)+N*w*upsilon*(N*w-z))*S(t)^2+(-z^2*eta*alpha*(C[max]*w*N-alpha*Q(t))*K(t)^2-(eta*alpha^2*Q(t)^2-2*C[max]*w*N*eta*alpha*Q(t)+N*w*((2*N*w-2*z)*alpha+N*C[max]^2*w*eta))*z*upsilon*K(t)-N*w*upsilon^2*(N*w-z)*(C[max]*w*N-alpha*Q(t)))*S(t)-N*w*z*alpha*upsilon*K(t)^2*(N*w-z))/((2*S(t)^2*alpha*z+(3*z*alpha*K(t)+upsilon*(C[max]*w*N-alpha*Q(t)))*S(t)+K(t)^2*alpha*z)*N*w*upsilon)

where initials conditions are:

S(0) = S0, K(0) = K0, Q(0) = Q0

Thanks,

Dmitry

 

 

 

Hello,

 

I am trying to solve the equation (non-linear) with one variable t2 (please see bellow):

(35595.29412*(52040.0-2400.0*t2))*(11-t2)*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-360.0*t2+59200.0))*t2)*exp(ln(52040.0-2400.0*t2)-8.804313725+.5176470590*t2)*(360000*(exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-360.0*t2+59200.0))*t2))^2+(620*(-360.0*t2+29600.0))*(1200*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-360.0*t2+59200.0))*t2)-2.232000*10^5*t2+1.83520000*10^7))*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-2760.0*t2+59200.0))*t2)/(360000*exp(ln(52040.0-2400.0*t2)-8.804313725+.5176470590*t2)*(exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-360.0*t2+59200.0))*t2))^2+(372000*((52040.0-2400.0*t2)*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-2760.0*t2+59200.0))*t2)+(-360.0*t2+29600.0)*exp(ln(52040.0-2400.0*t2)-8.804313725+.5176470590*t2)))*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-360.0*t2+59200.0))*t2)+(384400*(52040.0-2400.0*t2))*(-360.0*t2+29600.0)*exp(ln(-360.0*t2+29600.0)-(0.9803921570e-5*(-2760.0*t2+59200.0))*t2))^2 = 1/150

During evaluation of the solve command I received a warning that solutions may have been lost. How can I overcome this problem? Also, I need that t2>0.

Thanks in advance,

 

Dmitry 

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